Computational Fluid Dynamics (CFD) simulations of rotorcraft aerodynamics and ship airwakes are conducted using an immersed boundary method (IBM) in OpenFOAM. An IBM is coupled with a wall function and an actuator surface model (ASM), and this new approach enables a fully automated meshing of complex geometries and moving body simulations without a mesh deformation. The Georgia Institue of Technology (GIT) airframe is studied for the rotorcraft simulation, where an unsteady rotor is represented by the ASM. The Simple Frigate Shape 1 (SFS1) is investigated in the ship airwakes simulation. Simulation results are compared with both experimental measurements and computational data from those with a bodyconformal mesh. Results are competitive with existing best methods using a fraction of the setup and computational effort of the body-conforming method.